Definitive Wheel and Tire Thread with Pics


cobrar1339

GT Owner
Mark IV Lifetime
Feb 2, 2006
956
Diamond Bar, Ca
http://www.michelinman.com/tires/ul...&vehicleSearch=false&fromCompare1=yes&place=0

Michelin spec link



Is there a reason no one is looking at the Pilot Sport Cups for traction tires ?
Street legal, thread wear 80. Like a Nitto. A few of the Vet guys run these, more use the Nitto's due to price, but a decent arrive and drive track day tire as well. They last longer on the Vets than the Nittos as well. Think Legal Hoosier with some rain thread.

Note:
Different mfg's use specs that do not compare very well. Example one is giving diameter measured on a 8" wheel and the other on a 8.5" wheel. I am not a tire measurement guru. But seams to me that if the PS2's work fine the Cups would also.

Front
235/40/18 Cup 25.4 tall 9.5 on 8.5" rim looks to be .3 narrow vs. PS2 245/40/18 which lists 9.8 on a 8.5" rim.

It's Also .3 shorter. BTW the Goodyears actually measure 25.5 on the car. This may be due to the variance in rim width vs. the one they use for the spec. Also the sidewalls on these are more squared off than the Goodyears that seam to make them look taller on the vettes to me.


345/40/19 27.2" tall 13.8 on 12" rim available in PS2 or Cup.
 

cobrar1339

GT Owner
Mark IV Lifetime
Feb 2, 2006
956
Diamond Bar, Ca
One more , a test on the Sport cups. If the Dunlops ever come around they may look like this.


http://www.tirerack.com/tires/tests/chartDisplay.jsp?ttid=36

Browse around and you wil find more details on these and some ratings by users.
 

B O N Y

MODERATOR & FGT OWNER
Mark IV Lifetime
Sep 5, 2005
12,110
Fresno, Ca.
Contact Alex for alignment settings to dial in/out oversteer/understeer. Alex knows, my gal is neutral to slight oversteer, zero push.
 

HeritageBruce

GT Owner
Mark II Lifetime
Mar 13, 2006
746
Southern CA
Wally,
When you are referring the the PS Cups being available in the rear size, are you referring to the '08 Viper spec PS Cups? Where can I get some specs on these as Michilin's web site only listed 325 width as the widest size.
BTW, I use the PS Cups on my Challenge Stradale and they are very good tires, even though they take a while to heat up but once up to temps, they stick like glue.
 

BlackICE

GT Owner
Nov 2, 2005
1,413
SF Bay Area in California
345/40/19 27.2" tall 13.8 on 1...2" tall. That is over 1" smaller in diameter.
 

DoctorV8

GT Owner
Mark IV Lifetime
Feb 28, 2006
1,169
Houston
Nice pics, Kevin!

A buddy of mine saw/heard you at Memorial Park recently...called me thinking it was my car. :biggrin

Sanjay
 

GTforever

Member
Dec 7, 2007
12
Germany
The Corsa 265/40/18 and 345/35/19 I have on my car.
The 265 are not (yet?) in the Pirelli list ,but must be produced
for somebody.I got from my german tireshop.
Don´t know how they perform because of the winterweather here.
 

HeritageBruce

GT Owner
Mark II Lifetime
Mar 13, 2006
746
Southern CA
Bruce, what's the word on the tires? I need to replace mine, and I really do not want to go back to the Goodyears.
All I know for now is the RE050A's are quieter and ride better. My car isn't running too good (pinging) right now so I'll wait until that's fixed before I can hammer the car. I promise I'll post performance impressions as soon as I'm able to do a few spirited runs.
 
H

HHGT

Guest
All I know for now is the RE050A's are quieter and ride better. My car isn't running too good (pinging) right now so I'll wait until that's fixed before I can hammer the car. I promise I'll post performance impressions as soon as I'm able to do a few spirited runs.
Okay Bruce, you need to take one for the team. Stop by my house this weekend and we'll take off your tires/wheels and put them on my car and I'll shave off a few millimeters off the rubber and then report back to the forum.

Hummm, Orange on Red....
 

kosupply

GT Owner/Board of Directors
Mark IV Lifetime
Jan 27, 2006
236
Houston
Nice pics, Kevin!

A buddy of mine saw/heard you at Memorial Park recently...called me thinking it was my car. :biggrin

Sanjay
I was out for a run in the park....we need to try to hook up .
 

AZGT

GT Owner
Mark IV Lifetime
Dec 20, 2005
1,349
Scottsdale, AZ.
I almost tried this combo . I just ordered my third set of Bridgestones.... Iwould be interested if the the big rears push the skinny fronts...
Front and rear added about 1 inch in width, so shouldn't really be any different than stock.
 

AZGT

GT Owner
Mark IV Lifetime
Dec 20, 2005
1,349
Scottsdale, AZ.
Here is a good tire size calculator.

http://www.net-comber.com/tirecalc.html
 

HeritageBruce

GT Owner
Mark II Lifetime
Mar 13, 2006
746
Southern CA
Okay Bruce, you need to take one for the team. Stop by my house this weekend and we'll take off your tires/wheels and put them on my car and I'll shave off a few millimeters off the rubber and then report back to the forum.

Hummm, Orange on Red....
Sam,
I have a better idea... take your Whippled engine out of your car and put it in mine. Go team Heritage....
 

STORMCAT

GT
Mark IV Lifetime
Le Mans 2010 Supporter
May 25, 2006
7,413
Ft. Lauderdale
Bridgestone Specs a Word of Caution

I just received my rear Bridgestone Tires. I too am going to run the 345/35/ 19 Potenza RE050A Scuderia's on the rear. For the record these tires are the highest speed rated tires you can buy for our application. besides the ZR rating there is a bracket "Y" or ( Y ) which is good for over the 186 mph rating. We know the Enzo runs 212 mph so these are not the issue.

The word of caution comes on the speed rating for the front tire selection. I'm going with the Stock size Front : Bridgestone RE050A 235/ 45 / 18 these are ZR and Bracketed "Y" (Y) speed rated. Luke ( ext 362 ) at the Tire Rack informed me that the same tire in the 255/ 40 /18 is not a bracketed Y (Y) tire and carries a lower speed rating. I have run my car over 200 MPH and I want to have bracketed Y ( Y) tires for piece of mind.

The 18" front tires are not a Scuderia series tire. The performance specs ( grip , wear etc. ) match the Scuderia so they should match the rears well. The BS 235/45/18 will have a higher grip level than stock . So my take is that you have raised the grip level of the car at both ends but you still have left the designed push at the front. Now having said this I didn't ask about the 265 width speed rating that HB is running..
 
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HeritageBruce

GT Owner
Mark II Lifetime
Mar 13, 2006
746
Southern CA
The 265 fronts have a (101Y) rating, so it is also rated BEYOND 186 MPH and 101 meaning it is rated for 1819 pounds, the Scuderia rears are (110Y) rated for 2337 pounds. I'm hoping the new tires will make the car understeers less, and thus enable me to stiffen the front shocks to improve turn-in as I feel this is one of the GT's very few weak performance traits, when compared to cars such as Porsche's 996GT3, Ferrari's Challenge Stradale, or the Lotus Elise.
 
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SYCO GT

GT Owner
Mark II Lifetime
Sep 9, 2006
4,300
California
AZGT - I think it's a good look that you have without the large center caps. I also like the factory standard look too with the cap.
 

HeritageBruce

GT Owner
Mark II Lifetime
Mar 13, 2006
746
Southern CA
The 18" front tires are not a Scuderia series tire. The performance specs ( grip , wear etc. ) match the Scuderia so they should match the rears well. The BS 235/45/18 will have a higher grip level than stock . So my take is that you have raised the grip level of the car at both ends but you still have left the designed push at the front. Now having said this I didn't ask about the 265 width speed rating that HB is running..
Brian,
I'd think twice before running the same size fronts but go up from 315 to 345 sized rears. The car is already pushing quite a bit and if you throw a 9.5% increase in tread width in the rear, this may make the car push like a front driver.
Bruce
 

BlackICE

GT Owner
Nov 2, 2005
1,413
SF Bay Area in California
I don't have a huge concern about a little height difference front to rear, since I have T&A perches and can adjust to compensate if needed. I have no 1st hand experience with these tires, but from what has be posted, I think the Bridgestones vs. GY the BS should be better for the street because they have better grip during acceleration, but on the road coarse the GY are a little better. However if you are serious about the track you would be running Hoosiers.
 

BlackICE

GT Owner
Nov 2, 2005
1,413
SF Bay Area in California
How about some adjustable swaybars too allow us to dial out the understeer? I wonder does Alex have any data from testing in the past.
 
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cobrar1339

GT Owner
Mark IV Lifetime
Feb 2, 2006
956
Diamond Bar, Ca
I have the PS2's in 245/40ZR18 and 345/30ZR19 on stock wheels and they fit and look perfect. In fact, I found a formula for determining optimum wheel size for different size tires, and it indicated our 11.5" rear is the optimum size wheel for 345's. If you go with a 30 sidewall, it reduces the wheel height .7 inches which creates about a 10% increase in acceleration and uncorrected speedometer error...so hold on to your hat :biggrin I assume a 35 sidewall would increase acceleration about 5%...and a 40 will have no noticeable effect. As I recall, the tire width also nominally influences the wheel height. I love the PS2's :cheers
I started thinking about the CUPs when I saw this post. The same size rear is available in CUP but the fronts are a hair smaller.

Originally Posted by cobrar1339
345/40/19 27.2" tall 13.8 on 12" r...used anyone. Heck maybe I an confused. :willy